The present invention relates to an oscillation-type compressor preferably used in a refrigerator and an air-conditioner.
Various conventional oscillation-type compressors are disclosed in Published Japanese Patent Applications Nos. Kokai 51-57009, Kokai 8-247025, Kokai 9-324764, and Kokai 4-347460.
The oscillation-type compressors basically comprise a movable element including a piston and a stationary element including a cylinder, so that gas is introduced into a compression chamber defined by the piston and the cylinder and compressed by the piston that reciprocates in the axial direction.
An object of the present invention is to provide an oscillation-type compressor capable of minimizing the top clearance of the piston in a given piton stroke and maintaining efficient compressor operations.
Another object of the present invention is to realize a practical cooling device, such as a refrigerator, which is capable of automatically increasing the stroke of the piston in response to a high ambient air temperature so that the cooling power can be sufficiently obtained even in such a high load condition and. is also capable of automatically reducing the stroke of the piston in response to a decreased ambient air temperature, thereby realizing efficient compressor operation in accordance with the driving conditions of the cooling device without using additional detecting and control devices.
Another object of the present invention is to provide an oscillation-type compressor capable of suppressing the top clearance of the piston even in the start-up operation where the piston is operated with short strokes, thereby realizing efficient compressor operation.
Another object of the present invention is to provide an oscillation-type compressor capable of stabilizing the cylinder position during an ordinary operation.
Another object of the present invention is to provide an oscillation-type compressor capable of optimizing the piston position with respect to the cylinder position irrespective of changed operating pressure conditions, thereby minimizing the top clearance and realizing efficient compressor operation.
Another object of the present invention is to provide an oscillation-type compressor capable of preventing the piston from colliding with the exhaust valve when the piston stroke is increased, thereby eliminating any damage and noise.
Another object of the present invention is to provide an oscillation-type compressor having an exhaust or intake pipe shiftable in the axial direction even when large vibration occurs in the axial direction, thereby reducing a large amplitude stress repetitively acting on the exhaust or intake pipe.
In order to accomplish the above and other related objects, one aspect of the present invention provides an oscillation-type compressor comprising a tightly closed casing having an inside space for storing coolant gas, a block accommodated in the tightly closed casing, a motor including a stator and a mover, a piston connected to the mover of the motor, a movable element including the mover of the motor and the piston, a stationary element including the stator of the motor and the block, an elastic element having a portion fixed to the movable element and another portion fixed to the stationary element, a cylinder shiftable in an axial direction with respect the block, and a shifting device for shifting the cylinder in the axial direction.
Another aspect of the present invention provides an oscillation-type compressor comprising a tightly closed casing having an inside space for storing coolant gas, a block accommodated in the tightly closed casing, a motor including a stator and a mover, a piston connected to the mover of the motor, a movable element including the mover of the motor and the piston, a stationary element including the stator of the motor and the block, an elastic element having one portion fixed to the movable element and another portion fixed to the stationary element, a cylinder shiftable with respect the block, a cylinder head fixed to the cylinder, back-pressure chambers formed in the coolant gas space and airtightly partitioned by an integral unit including at least one of the cylinder and the cylinder head, and at least one of the back-pressure chambers being held at a low pressure level and another one of the back-pressure chambers being held at a high pressure level.
It is preferable that this oscillation-type compressor further comprises an elastic member having one end connected to the integral unit including at least one of the cylinder and the cylinder head and the other end connected to the stationary element, and further comprises a cylinder position detecting sensor fixed to one of the stationary element and the cylinder.
Another aspect of the present invention provides an oscillation-type compressor, comprising a tightly closed casing having an inside space for storing coolant gas, a block accommodated in the tightly closed casing, a motor including a stator and a mover, a piston connected to the mover of the motor, a movable element including the mover of the motor and the piston, a stationary element including the stator of the motor and the block, an elastic element having one portion fixed to the movable element and another portion fixed to the stationary element, a cylinder fixed to the block or shiftable in an axial direction with respect the block, a cylinder head fixed to the cylinder, an auxiliary pipe having one end shiftable in the axial direction with respect to one of an exhaust pipe and an intake pipe and the other end fixed to one of the cylinder and the cylinder head.
Furthermore, another object of the present invention is to provided an oscillation-type compressor capable of causing the cylinder to shift toward the top dead center when the ambient temperature is high and therefore the required cooling power is high.
Another object of the present invention is to provide an oscillation-type compressor capable of surely reducing the pulsation of the compressor even when the discharged gas amount increases in response to an increased stroke, thereby suppressing noise and vibration.
Another object of the present invention is to provide an oscillation-type compressor capable of preventing the compressor efficiency from deteriorating due to the leakage of coolant gas.
Another object of the present invention is to provide an oscillation-type compressor capable of preventing the cylinder from shifting excessively toward the top dead center, while causing no problems in the reliability of the elastic element or the like.
In order to accomplish the above and other related objects, one aspect of the present invention provides an oscillation-type compressor comprising a block and a piston accommodated in a tightly closed casing, a motor including a stator and a mover, a movable element including the mover and the piston, a stationary element including the block and the stator, an elastic element having a portion fixed to the movable element and another portion fixed to the stationary element, a cylinder accommodating the piston so that the piston is shiftable in an axial direction, the cylinder being inserted in the block so as to reciprocate in the axial direction with a closed space formed between the block and the cylinder, a cylinder head comprising an exhaust chamber and attached to the cylinder, and a communication passage connecting the closed space and the exhaust chamber.
It is preferable that the above-described closed space is connected to an outside space via an exhaust pipe. And, a slide surface between the cylinder and the block is connected to a lower part of the closed space via a passage. A groove is provided on a slide surface of one of the cylinder and the block.
Furthermore, another object to the present invention is to provide an oscillation-type compressor capable of increasing the top clearance of the piston in response to a decreased ambient air temperature or a decreased load without deteriorating the operating efficiency of the compressor.
Another object of the present invention is to provide an oscillation-type compressor capable of causing the stator of the motor to shift in a direction opposed to the compression chamber when the top dead center position of the piston is dislocated toward the cylinder head, thereby preventing the piston from colliding with the exhaust valve.
Another object of the present invention is to provide an oscillation-type compressor capable of shifting the motor stator in the direction opposed to the compression chamber when the compressor is stopped.
In order to accomplish the above and other related objects, one aspect of the present invention provides an oscillation-type compressor comprising a tightly closed casing having an inside space for storing coolant gas, a cylinder accommodated in the tightly closed casing, a motor including a stator and a mover, a piston connected to the mover of the motor, a movable element including the mover of the motor and the piston, a stationary element including the stator of the motor and the cylinder, an elastic element having a portion fixed to the movable element and another portion fixed to the stationary element, a piton position detecting sensor detecting the position of the piston, top dead center position calculating means for calculating a top dead center position of the piston based on a piston position signal obtained from the piton position detecting sensor, amplitude control means for controlling an amplitude of the mover in accordance with a difference between the top dead center position and a selected top dead center reference value, and top dead center reference value changing means for changing the top dead center reference value.
Another aspect of the present invention provides an oscillation-type compressor comprising a tightly closed casing having an inside space for storing coolant gas, a cylinder and a block accommodated in the tightly closed casing, a motor including a stator and a mover, a piston connected to the mover of the motor, a movable element including the mover of the motor and the piston, a stationary element including the stator of the motor, the cylinder and the block, an elastic element having a portion fixed to the movable element and another portion fixed to the stationary element, the stator of the motor or a movable stator base connected to the stator being partly coupled with the stationary element so as to reciprocate in an axial direction in response to a pressure imbalance between back-pressure chambers formed therebetween, and a pressure control mechanism for controlling the pressures of the back-pressure chambers.
It is preferable that a shifting means is provided for shifting the stator of the motor. in a direction opposed to the compression chamber when the compressor is stopped.
Furthermore, another object of the present invention is to reduce the weight of a sensor core attached to the movable element to realize a compact displacement detector, thereby obtaining a higher resonance frequency and realizing a high power compressor.
Another object of the present invention is to provide a displacement detector having a limited detection range, thereby improving the accuracy in the measurement of the piston position in the vicinity of the top dead center.
Another object of the present invention is to provide the weight of the movable element, thereby suppressing vibration.
Another object of the present invention is to provide the cooling power from deteriorating due to the coolant gas leakage from the compression chamber.
Another object of the present invention is to reduce the slide loss between the cylinder and the piston, thereby improving the compressor efficiency.
In order to accomplish the above and other related objects, one aspect of the present invention provides an oscillation-type compressor comprising a block and a piston, a motor including a stator and a mover, a movable element including the mover and the piston, a stationary element including the block and the stator, an elastic element having a portion fixed to the movable element and another portion fixed to the stationary element, a cylinder accommodating the piston so as to allow the piston reciprocating in an axial direction, a displacement detector connected to the piston in the axial direction for detecting a position near a top dead center of the piston, top dead center position detecting means for obtaining the top dead center position of the piston based on a signal obtained from the displacement detector, current/voltage detecting means for detecting a current or voltage value of the motor, and power supply means for changing the voltage applied to the motor based on output signals of the top dead center position detecting means and the current/voltage detecting means.
Another aspect of the present invention provides an oscillation-type compressor comprising a block and a piston, a motor including a stator and a mover, a movable element including the mover and the piston, a stationary element including the block and the stator, an elastic element having a portion fixed to the movable element and another portion fixed to the stationary element, a cylinder accommodating the piston so as to allow the piston reciprocating in an axial direction, and a displacement detector attached to the movable element and the stationary element at a radially inward portion with respect to the stator of the motor.
Another aspect of the present invention provides an oscillation-type compressor comprising a block and a piston, a motor including a stator and a mover, a movable element including the mover and the piston, a stationary element including the block and the stator, an elastic element having a portion fixed to the movable element and another portion fixed to the stationary element, a rotational direction restricting mechanism for limiting the rotation of the elastic element about a piston shaft in a single direction, a cylinder accommodating the piston so as to allow the piston reciprocating in an axial direction, and a dynamic pressure generating mechanism provided on at least one of the piston and the cylinder.
Furthermore, another object of the present invention is to provide an oscillation-type compressor capable of sufficiently supporting the movable element in the radial direction at a portion other than the slide portion between the piston and the cylinder even when the piston is positioned near the top dead center or the bottom dead center and therefore the elastic element cannot sufficiently support the movable element in the radial direction due to reduced rigidity.
Another object of the present invention is to provide an oscillation-type compressor capable of preventing the piston from colliding with the cylinder head or the exhaust valve when the movable element including the piston shifts toward the compression chamber due to the insufficient pressurization occurring immediately after the startup of the compressor or when the ambient air temperature is low.
Another object of the present invention is to provide an oscillation-type compressor capable of preventing the movable element from excessively shifting away from the compression chamber in response to extremely changed operating conditions.
In order to accomplish the above and other related objects, one aspect of the present invention provides an oscillation-type compressor comprising a tightly closed casing, a piston and a cylinder accommodated in the tightly closed casing, a motor including a stator and a mover, a stationary element including the cylinder and the stator of the motor, a movable element including the piston and the mover of the motor, an elastic element having a portion fixed to the movable element and another portion fixed to the stationary element, and a support mechanism for supporting the movable element in a radial direction when the piston is positioned near a top dead center position or a bottom dead center.
Another aspect of the present invention provides an oscillation-type compressor comprising a tightly closed casing, a piston and a cylinder accommodated in the tightly closed casing, a motor including a stator and a mover, a stationary element including the cylinder and the stator of the motor, a movable element including the piston and the mover of the motor, an elastic element having a portion fixed to the movable element and another portion fixed to the stationary element, and a position changing mechanism associated with the movable element for changing an axial position of the movable element.
It is preferable that this oscillation-type compressor further comprises a stopper for limiting an axial shift amount of the movable element changed by the position changing mechanism.